Evaluation of process behavior and crystallite specifications of mechano-chemically synthesized WC–Al2O3 nano-composites

• A new route for the synthesis of WC–Al2O3 composite has been introduced.
• WC–Al2O3 powder was synthesized by 6 h milling of WO3–1.8Al–1.56C mixture.
• Effect of process variables on crystallite size and lattice strain was studied.
• High reaction intensity results in a large crystallite size and low lattice strain.
• Longer milling times results in a smaller crystallite size and higher lattice strain.

A new route for the synthesis of WC–Al2O3 composite free from unwanted W2C phase through mechano-chemical treatment of WO3–xAl–y(4 − 1.5x)C mixture has been investigated. It has been concluded that by substitution of 10 mol% of 2 mol Al (x = 1.8) with equivalent stoichiometric amount of C together with 20 mol% excess carbon addition (y = 1.2), i.e., using a WO3:1.8Al:1.56C initial mixture, W2C free WC–Al2O3 composite can be successfully obtained by about 6 h milling. Crystallite size and lattice strain of the WC–Al2O3 composite synthesized in the present study as well as those obtained by the previous successful routes have been reported. The results revealed that a powder whose synthesis route involves lower adiabatic temperature as well as longer milling time would have a smaller crystallite size and higher lattice strain. Furthermore, TEM observations showed that all synthesized powders contain the agglomerates which consist of nano-size particles.

Figure optionsDownload as PowerPoint slide